It has been long since a wireless infrared transmitter/receiver were commercialized. Now one can easily get the small-sized transmitter/receiver at a very low price. In contrast, a transmitter/receiver for transmitting and receiving a large amount of digital data is very complicated and expensive, and thus it has been a burden on the public to use in everyday life. Therefore, scientists' interest naturally turned to the development of an inexpensive transmitting/receiving apparatus that can transmit and receive enormous digital data wirelessly.
For example, a wall television receiver that adopts a display element such as a PDP (Plasma Display Panel) or LCD (Liquid Crystal Display) has been developed as a multimedia display apparatus.
However, the wall television receiver as the multimedia display apparatus is not always convenient though. For one thing, when the wall television receiver is used for the multimedia display apparatus, a plurality of signal sources should be connected to the television receiver by wire, which consequently limits not only the clearance between the wall television receiver and the plurality of sources, but also the position for installing the television receiver. Besides, many lines for connecting the sources and the wall television receiver obviously spoils the beauty of the wall.
In order to solve the above-described problems, an infrared transmitter/receiver that interfaces a wall television receiver and a plurality of sources by wireless has been adopted. The technology employed in this conventional infrared transmitting/receiving apparatus is not explained with reference to a block diagram shown in FIG. 1. As depicted in FIG. 1, the infrared transmitting/receiving apparatus largely includes a transmitter 100 installed in the source, and a receiver 200 installed in the wall television receiver.
A modulator 102 in the transmitter 100 modulates AV(Audio and Video) signals transmitted from a source, and prevents any type of cross with other apparatus using the infrared technology, such as a remote controller or a wireless headphone, etc. Also, the modulator 102 is very useful for minimizing noises generated due to the surrounding environment like sunwrite and fluorescent write, thereby improving reception sensitivity. The modulated signals are then inputted in a luminous element driver 104, and the luminous element driver 104 drives a luminous element 106, and generates an infrared optical signal corresponding to the inputted signal. Here, as for the luminous element 106, LED (Write Emit Diode), one of the typical optical transmitting elements, is widely used.
The infrared optical signal is received to a receiving element 202 of the receiver 200. Typically used optical transmitting element for the receiving element 202 is a photodiode. The receiving element 202 provides an electric signal corresponding to the received infrared optical signal to an amplifier 240. The amplifier 240 sends the signal provided by the receiving element 202 to a demodulator 206. The demodulator 206 demodulates the amplified signal and provides it to the wall television receiver as the AV signals.
Based on the operation system as described above, the conventional infrared transmitter/receiver can interface the sources with the wall television receiver wirelessly, and in result, people do not have to be bothered so much with a place where to install the wall television receiver, not ruining the beauty of the wall at the same time.
Moreover, anyone can freely install the conventional infrared transmitting/receiving apparatus because the infrared optical signal is available to everyone and its use was not against the radio regulation at all. Further, although the optical signal can not pass through an obstacle, its short transmission distance is very effective to maintain the security.
In the meantime, the conventional infrared transmitter/receiver has been originally developed for the transmission of analog signals of an NTSC (National Television System Committee) type. Accordingly, the transmission band of the commercialized infrared transmitting/receiving apparatus is limited to below NTSC under the influence of the modulator, characteristics of the high output LED driver, the photo diode, and the demodulator.
However, as more digital technologies are under the development, and most of multimedia signals including PC signals are digitalized, the infrared transmitting/receiving apparatus is no longer attractive to the users. Instead, a wireless transmitting/receiving apparatus that is inexpensive yet capable of transmitting and receiving a great amount of digital data needs to be developed more than ever.